Method and system of varying mechanical vibrations at a microphone

ABSTRACT

An improved method and system for varying an amount of mechanical coupling in a speakerphone is disclosed. Solutions and implementations provided vary the amount of mechanical coupling between one or more speakers and one or more microphones of the speakerphone to generate high-quality sounds. Implementations include receiving a signal for a first speaker, transforming the signal to send to a second speaker or actuator to generate either complementary or opposing vibration forces to those generated by the first speaker, and an accelerometer to measure the amount of vibration caused by the speaker and adjust the transformation applied to the signal to increase or decrease the amount of mechanical coupling, as needed.

TECHNICAL FIELD

This disclosure relates generally to improving design of speakerphonesand, more particularly, to a system and method of varying signalcoupling between one or more speakers and one or more microphones in aspeakerphone.

BACKGROUND

With the rise in use of small electronic devices such as mobile phonesin recent years, there has been a significant increase in the need fordesigning and producing high quality speakerphones that are small insize. A key design challenge for such small speakerphones is to minimizecoupling between the one or more microphones and the one or morespeakers. The coupling is composed of acoustic, mechanical, andelectrical coupling.

In general, reducing electrical coupling in a speakerphone is lesschallenging than minimizing acoustic and mechanical coupling. Variousmethods have been used in the industry to reduce acoustic and mechanicalcoupling, but most have several disadvantages. For example, somehigh-quality speakerphones minimize mechanical coupling by using rubbermounts for the speaker and/or microphones. The rubber mounts, however,tend to occupy a lot of space and to be fragile, thus creating asignificant design challenge for speakerphones that need to fit within asmall space and be robust.

An alternative method of reducing acoustical and mechanical couplinginvolves creating distance between the one or more microphones and thespeaker. This also raises the issue of size in speakerphones which areoften designed as accessories for mobile devices or personal computers.

SUMMARY

Apparatuses and methods of varying an amount of mechanical coupling in aspeakerphone are described. Disclosed apparatuses include an apparatushaving a microphone, a first speaker having a first mass, the firstspeaker configured for receiving a first input signal, and a secondspeaker having a second mass, the second speaker configured forreceiving a second input signal. In one implementation, the firstspeaker and the second speaker are positioned back to back with thefirst speaker facing a first direction and the second speaker facing asecond direction that is opposite that of the first direction, and thesecond speaker is configured to, in response to the second input signal,generate a second vibration force that is in an opposite direction tothat of a first vibration force generated by the first speaker andoffsets at least part of the first vibration force generated by thefirst speaker.

In at least one implementation, disclosed apparatuses include anapparatus having a microphone, a first speaker configured for receivinga first input signal and generating a first vibration force, a signaltransformation unit receiving the first input signal and performing asignal transformation thereon to produce a transformed input signal forvarying an amount of mechanical vibration at the microphone, and asecond speaker configured for receiving the transformed input signal andgenerating a second vibration force. In one implementation, acombination of the first vibration force and the second vibration forcevaries the amount of mechanical vibration at the microphone.

Disclosed methods can include varying an amount of mechanical couplingbetween at least one microphone and one or more speakers in aspeakerphone by receiving an input signal, sending a copy of the inputsignal to a first speaker, determining if a signal transformation isneeded for the input signal to vary an amount of mechanical coupling,upon determining that the signal transformation is needed, performingthe signal transformation on the input signal to produce a transformedinput signal, and transmitting the transferred input signal to a secondspeaker. In one implementation, the first speaker generates a firstvibration force, the second speaker generates a second vibration force,and a combination of the first vibration force and the second vibrationforce varies the amount of mechanically coupled vibrations from one ormore speakers to one or more microphones.

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter. Furthermore,the claimed subject matter is not limited to implementations that solveany or all disadvantages noted in any part of this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawing figures depict one or more implementations in accord withthe present teachings, by way of example only, not by way of limitation.In the figures, like reference numerals refer to the same or similarelements. Furthermore, it should be understood that the drawings are notnecessarily to scale.

FIG. 1 is a schematic representation of an improved speakerphone wheremechanical coupling has been reduced.

FIGS. 2A-2B are schematic representations of alternative improvedspeakerphones where mechanical coupling has been reduced.

FIG. 3 is a schematic representation of an improved speakerphone wheremechanical coupling has been reduced by using an actuator.

FIG. 4 is a schematic representation of an alternative improvedspeakerphone where mechanical coupling has been reduced by using anactuator.

FIG. 5 is a flow diagram for a method for adjusting the amount ofmechanical coupling between one or more speakers and one or moremicrophones in a speakerphone.

DETAILED DESCRIPTION

In the following detailed description, numerous specific details are setforth by way of examples in order to provide a thorough understanding ofthe relevant teachings. It will be apparent to persons of ordinaryskill, upon reading this description, that various aspects can bepracticed without such details. In other instances, well known methods,procedures, components, and/or circuitry have been described at arelatively high-level, without detail, in order to avoid unnecessarilyobscuring aspects of the present teachings. In the following material,indications of direction, such as “top” or “left,” are merely to providea frame of reference during the following discussion, and are notintended to indicate a required, desired, or intended orientation of thedescribed articles.

One of the key challenges in designing high-quality speakerphones isminimizing mechanical coupling. The coupling is particularly moreevident in small speakerphones where the distance between the one ormore microphones and the speaker is small. In general, the amount ofmechanical vibration at a microphone is reduced by a factor of 1/R²,where R is the distance between the speaker and the microphone. Thus,when the distance, R, is small, there is more mechanical coupling. Thelimited space also restricts the use of possible methods that can beused to minimize this coupling.

Another restriction on the use of possible techniques to reduce themechanical coupling between a speaker and microphone is caused becauseof the type of mechanical coupling generated in a speakerphone. Ingeneral, mechanical coupling between the microphone and the speakerincludes significant amounts of non-linear coupling. This can beproblematic, as linear filters used for echo cancellation cannot removethis type of non-linear coupling. As a result, a non-linear echocanceler or echo suppression needs to be used to reduce the non-linearcoupling. The use of a non-linear echo canceler, however, tends to makethe speakerphone more simplex, thus reducing a user's ability to hear aperson on the other end of the line, when the user is speaking. Anon-linear echo canceler also makes the signal processing moredemanding, rising the performance requirements and thus cost of signalprocessing unit.

In the present implementations, various techniques are used to minimizemechanical coupling by designing a speakerphone that utilizes twospeakers or a combination of a speaker and an actuator, where the secondspeaker or actuator generates vibrations with an equal but opposingforce of vibrations generated by the first speaker, such that the netvibration force from the speakers or speaker and actuator combinationbecomes close to zero.

As will be understood by persons of skill in the art upon reading thisdisclosure, benefits and advantages provided by such implementations caninclude, but are not limited to, a solution to the problem of designinghigh-quality speakerphones that are small in size and provide a duplexdevice which enables the user to talk and hear the person on the side atthe same time. Solutions and implementations provided here improve thequality of the speakerphone by reducing the amount of mechanicalcoupling, while keeping the size of the speakerphone small. Moreover,the design is simple and inexpensive to implement and can circumvent theneed for using means to tie down other elements in the speakerphone toreduce vibration, thus saving design and production costs.

Referring now to the drawings, FIG. 1 is a schematic representation of asimplified example speakerphone 100, which can be utilized to reducemechanical coupling, in accordance with one or more aspects of thepresent implementations. Speakerphone 100 includes, among otherfeatures, a first speaker 105 and a second speaker 110, with the secondspeaker 110 having similar features as those of the first speaker 105.For example, the second speaker 110 may be of approximately the samesize, the same mass, and use the same amount of power as that of thefirst speaker 105. In one implementation, the first and the secondspeakers are identical, such that when the same input signal is receivedby the first and the second speakers 105 and 110, the amount ofvibration force caused as of result of the acoustic signal generated byeach speaker is approximately the same. In such a configuration, becausethe speakers are facing in opposite directions, the vibration forcegenerated by each speaker is the same but directed in oppositedirections. As a result, according to Newton's third law, the netvibration force becomes close to zero.

In speakerphone 100, the first speaker 105 is positioned directly abovethe second speaker 110, in a back to back configuration, with the firstspeaker 105 and the second speaker 110 facing the opposite directions,such that any vibration force generated by the first speaker can bedirectly counteracted by the amount of vibration force generated by thesecond speaker. In an alternative implementation, first and secondspeakers 105 and 110 may reverse positions such that the second speaker110 is positioned directly above the first speaker 105. This would notchange the effects of the vibration forces. In an alternativeimplementation, the configuration may be rotated 90 degrees so that thespeaker cones are facing left and right instead of up and down. Thiswould not change the effects of the vibration forces.

In yet another implementation, the second speaker 110 may not bepositioned directly below the first speaker 105. For example, the secondspeaker 110 may be positioned slightly to the left or to the right ofthe first speaker 105. This may occur, because of design requirements orspace restrictions. Because of the small size of the speakerphone 100, aslight movement to the side of the second speaker 110 would generallynot change the effectiveness of the counteractive vibration forces.

In speakerphone 100, the second speaker 110 is attached to the firstspeaker 105. This may maximize the canceling effects of thecounteractive vibration forces generated by the second speaker 110, asdiscussed further below, or may simply be done to keep the secondspeaker 110 in place. Alternatively, the second speaker 110 may simplybe positioned below the first speaker, without the two speakers beingdirectly attached. In such a configuration, a rigid coupler may be usedbetween the speakers. In one implementation, the second speaker 110 mayinclude a low-pass filter at a frequency, such as 1000 Hz, which is thefrequency range that most vibrations are created. By filtering out thehigh frequencies there is no phase interference in the high frequencies.

Speakerphone 100 also includes a microphone 115 and a vibrationmeasurement unit, such as, an accelerometer 120. In one implementation,accelerometer 120 is mounted next to the microphone to detect the amountof vibration present around the microphone. This is because even withthe opposing vibration forces generated by the second speaker 110, theremay still be some vibration present around the microphone. Theaccelerometer can detect the presence of vibration and determine theamount of it. The accelerometer may have a sample rate of 2 KHz or more.Alternatively, a bone-conducting microphone can be used which acts likean accelerometer. In alternative implementations, the accelerometer 120may be located close to the first speaker or the second speakers 105 and110 for measuring the vibration at its source. The accelerometer mayalso be located anywhere else inside the speakerphone.

The information collected by the accelerometer can be used in a feedbackmechanism to transform the input signal sent to the second speaker 110to change the parameters of the vibration force generated by the secondspeaker 110 in order to minimize the amount of mechanically coupledvibration at the microphone. This feedback mechanism is discussed inmore detail below. In one implementation, an accelerometer may be usedduring manufacturing of the speakerphone to perform a factory tuning. Inthis manner, the amount of vibration may be determined once duringtuning at the factory. This amount may then be used during the life ofthe speakerphone to adjust the input signal sent to the second speaker110. By using this technique, the need for including the accelerometerin the speakerphone 100 may be eliminated, resulting in cost and spacesavings in the speakerphone 100. Alternatively, the accelerometer 120may be included in the system 100 as shown to perform live adjustmentsover the life of the product. This may be useful since, because ofdifferent temperatures and/or other changes occurring as the productages, the performance of the first and/or the second speakers 105 and110 may change.

Microphone 115 can be any microphone suitable for a speakerphone device.The microphone may be positioned on a rubber boot, may be directly gluedto a surface of the speakerphone 100, or may be positioned on a PowerControl Panel (PCP) or Printed Circuit Board (PCB) of the speakerphone100. In one implementation, more than one microphone may be present. Insuch a configuration, depending on the location of the additionalmicrophones, one or more additional accelerometers may be used to detectvibration around each of the microphones. For example, if the secondmicrophone is on the other side of the first and the second speakers 105and 110, then a second accelerometer may be utilized. The output of themultiple accelerometers may then be used in a transform functioncalculated to minimize the amount of vibration as much as possiblearound each of the several microphones. If, however, the secondmicrophone is on the same side and/or close to the first microphone,then the same accelerometer may suffice for detecting the presence andamount of vibration around both microphones. In an alternativeimplementation, the accelerometer is placed on the frame or magnet ofone of the speakers, or close to them, to measure and minimize thevibration at the source, thus minimizing the vibration coupled to themicrophones.

By providing a second speaker 110 that generates nullifying vibrationforces, speakerphone 100 can minimize mechanical vibrations at itssource. In addition to reducing mechanical coupling between the speaker105 and the microphone 115, this also minimizing vibrations throughoutthe entire device. As a result, the improved speakerphone 100 eliminatesthe need for wrapping loose wires and/or utilizing tie-downs for variousother components of the speakerphone which might otherwise causedistortion when they vibrate. This results in a simpler design whichreduces expenses associated with designing and manufacturing theimproved speakerphone. The resulting speakerphone can be have a volumeas small as less than 10 cubic centimeters.

FIG. 2A is a schematic representation of an alternative improvedspeakerphone 200, which can be utilized to reduce mechanical coupling.Like speakerphone 100, speakerphone 200 includes a first speaker 105, asecond speaker 110, a microphone 115, and an accelerometer 120. Thecomponents have similar features and characteristics as those ofspeakerphone 100, and as such, will not be discussed here in detail.

In speakerphone 200, instead of the speakers being positioned directlyback to back, a mechanical coupling block 210 is positioned in betweenthem. The mechanical coupling block may be a rigid block such as aplastic part. This may be necessitated, for example, by designparameters of the speakerphone 200. Even though, the first and thesecond speakers 105 and 110 are not back to back, in thisimplementation, the vibration forces generated by the second speaker 110can still nullify those generated by the first speaker 105. However,because the first and the second speakers 105 and 110 are located indifferent places within the speakerphone 200, they may be in twodifferent acoustical environments and thus may radiate differently. As aresult, the input signal sent to the second speaker 110 may be passedthrough a filter first, to ensure that the counteractive vibrationforces generated by the second speaker 110 have the desired effect ofnullifying mechanical vibrations at the microphone location.

FIG. 2B is a schematic representation of another alternative improvedspeakerphone 250, which can be utilized to reduce mechanical coupling.Like speakerphones 100 and 200, speakerphone 250 includes a firstspeaker 105, a second speaker 110, a microphone 115, and anaccelerometer 120. These components have similar features andcharacteristics as those of speakerphones 100 and 200, and as such, willnot be discussed here in detail. Speakerphone 250 also includes a thirdspeaker 260.

In speakerphone 250, the third speaker 260 faces the same direction asthat of the first speaker 105, while the second speaker 110 faces theopposite direction. This may be necessitated by design parameters of thespeakerphone 250. In such a configuration, the input signals sent to thesecond speaker 110 and the third speaker 260 may be generated such thatthe sum of vibration forces generated by the first, second and thirdspeakers in the x and y directions is close to zero.

FIG. 3 is a schematic representation of an improved speakerphone 300which uses an actuator and can be utilized to reduce mechanicalcoupling. Speakerphone 300 includes a speaker 305, an actuator 310, amicrophone 315, and an accelerometer 320. The speaker 305, microphone315, and accelerometer 320 have similar features and characteristics assimilar components of speakerphone 100, and as such, will not bediscussed here in detail.

The actuator 310, in one implementation, is a speaker without a cone.Because the actuator 310 does not have a cone, it can face anydirection. The use of the actuator 310 may be advantageous, as itoccupies less space than a speaker, while still achieving the samenullifying results. In general, the actuator 310 has a different movingmass than that of a speaker and a different sensitivity. As a result, inone implementation, the input signal sent to the actuator 310 could notbe the same as the input signal sent to the speaker 305. Instead, a copyof the same signal sent to the speaker 305 would need to receive phaseand/or amplitude transformation for the actuator to generate an equalbut opposite vibration force as that of the speaker 305. In analternative implementation, the actuator 310 may have a moving mass thatis close to the moving mass of the speaker 305, and motors of thespeaker 305 and actuator 310 may have similar enough characteristics atthe frequency range of interest. In such a configuration, the same inputsignal sent to the speaker 305 may be sent to the actuator 310 foroptimal reduction of vibration.

FIG. 4 is a schematic representation of an alternative improvedspeakerphone 400 using an actuator, which can be utilized to reducemechanical coupling. Speakerphone 400 includes a speaker 405, anactuator unit 410, a microphone 415, and an accelerometer 420. Thespeaker 405, microphone 415, and accelerometer 420 have similar featuresand characteristics as similar components of speakerphone 300, and assuch, will not be discussed here in detail. The actuator unit 410 mayinclude one, two or three actuators in the x, y and z directions. Thisis because the vibrations at the speakers are primarily in the z-axis,but at the microphone they can be in the x, y and z direction. Forimproved reduction of vibrations at the microphone location, two orthree one-dimensional actuators may be needed.

In speakerphone 400, instead of being positioned back to back with thespeaker 405, the actuator 410 is located next to the microphone 415. Inone implementation, the actuator unit 410 may be positioned on themicrophone. The actuator unit 410 may also be attached to the microphone415. The proximity of the actuator unit 410 to the microphone 415 may benecessitated by design parameters of the speakerphone 400 or so thatvibrations are canceled at the microphone. Although, the speaker 405 andactuator unit 410 are not back to back in speakerphone 400, thevibration forces generated by the actuator 410 can still cancel outthose generated by the speaker 405. However, because the speaker 405 andthe actuator 410 are located in different places within the speakerphone400, the coupling from the speaker 405 to the microphone 415 may bedifferent from the coupling from the actuator 410 to microphone 415.Thus, the input signal sent to the speaker 405 may need moremodification before being sent to the actuator unit 410, to ensure thatthe counteractive vibration forces generated by the actuator unit 410have the desired nullifying effect at the microphone.

FIG. 5 is a flow diagram depicting an exemplary method 500 for adjustingthe amount of mechanical coupling between one or more speakers and oneor more microphones in a speakerphone, which may be performed, forexample, using the system 100 illustrated in FIG. 1. At 510, the method500 includes receiving an input signal for the first speaker. This maybe the electrical signal that is received by a speakerphone forgenerating sound. In general, in prior art speakerphones, this signal issent directly to the speaker to produce sound. In method 500, however,the received signal is split into two with a copy being sent directly tothe first speaker to generate sound in a normal manner, at 520, whileanother copy is kept for the second speaker, as discussed further below.

Method 500 determines, at 530, whether transformation is needed for thesignal received by the speakerphone, before a copy of it is sent to thesecond speaker. This is determined by examining the speakerphone'sconfiguration and environment to determine if any transformation isneeded for the input signal of the second speaker to generate equal butopposing vibration forces that can nullify the effects of the vibrationforces generated by the first speaker. In the configuration used inspeakerphone 100 of FIG. 1, the amount of transformation needed may beminimal because of the back to back position of the first and secondspeakers. In that implementation, because the two speakers are, for themost part identical and they face opposite directions, a phase shift maynot be needed to generate equal but opposing vibration forces by the twospeakers. However, because of the different acoustical environments thatthe two speakers may be located in, some transformation may still beneeded to achieve the desired nullifying results. The transformation inspeakerphone 100 may involve applying a filter, such as a low passfilter. In alternative speakerphone implementations, more transformationmay be needed. For example, in speakerphone 250 of FIG. 2B, where thetwo speakers are facing the same direction, a 180 degrees phasetransformation may be needed for the signal sent to the second speaker.

In one implementation, the need for transformation and the type oftransformation needed is also determined by examining a mode ofoperation for the speakerphone. This is because, during a music mode,when the speakerphone is being used as solely a speaker, there may notbe a need for reducing mechanical coupling. In fact, more mechanicalvibration may be desirable to make the sounds produced more pleasing.For example, vibrating a table on which the speakerphone is placed maymake low frequency sounds more audible, which makes the music generatedby the speakerphone sound more pleasing.

In such an implementation, the device may have a music mode that,instead of reducing mechanical vibrations of the body of the device,increases it. This may be done by first determining whether the deviceis playing music or is being used as a speakerphone. This determinationcan be made, for example, by detecting if the microphone is open or not.When the microphone is not open, and the speaker is generating sound,the system may decide that it is in music mode or the microphone ismuted, in which case there is no fear of echo and thus no need to reducecoupling. The speakerphone may also have selectable modes that can bechosen by a user. Once the system determines that it is in music mode,then it may adjust the transform function used to transform the inputsignal sent to the second speaker or actuator such that it generatesmore vibration.

If it is determined, at 530, that a transformation is not needed for theinput signal, then the copy of the original signal received by thespeakerphone is fed into the second speaker, at 540, before method 500proceeds to step 570, as discussed further below. This may occur, in aback to back speaker configuration, such as the one in speakerphone 100,when it is determined that no filtration is needed to achieve thedesired nullifying results.

When it is determined that a transformation is needed, method 500proceeds to apply the required transformation, at 550. This may be done,in one implementation, by first determining the type and amount oftransformation needed. This can be achieved by determining the optimalphase and gain change required in order to minimize the root mean square(rms) of acceleration measured at the accelerometer for the samefrequency range. In one implementation, the rms of acceleration has beenmeasured previously (either during a previous live use or during factorytuning) and the amount is used to adjust a transform function used totransform the input signal. In one implementation, the transformfunction is a non-linear transform function in either time or frequencydomain. In the frequency domain, method 500 may transform the signal perfrequency or on a total wide-band basis.

Once the predetermined transformation is applied, the adjusted signal isfed into the second speaker and/or actuator, as the case may be, at 560,so that the second speaker can generate the desired vibration forces tocounteract those of the first speaker. Method 500, then, at 570,measures the amount of vibration at the microphone using anaccelerometer, such as the accelerometer 120 of speakerphone 100. Thatis because even if prior measurements or tuning have helped shape thetransform function, environmental causes may alter the speakerphone suchthat vibration still exists. Measuring the amount of vibration enablesthe system to adjust its transform function, as needed, thus creating alive feedback loop. As a result, once the amount of vibration ismeasured, method 500 proceeds to adjust the transform function, asneeded, at 580. In this manner, the transform function accounts forcurrent vibration e, as the input signal continues arriving at thespeakerphone or for future input signals. After the transform functionhas been adjusted, method 500 proceeds to end, at 590.

Apparatuses and methods of adjusting mechanical vibration in aspeakerphone are described. Methods can include receiving a signal for aspeaker, sending a copy of the signal to a first speaker, determining ifa transformation is needed for the signal before being sent to a secondspeaker and transforming the signal accordingly, sending the transformedsignal to the second speaker, measuring the amount of vibration at amicrophone in the speakerphone, and adjusting a transform function forthe input signal based on the amount of vibration detected at themicrophone.

Apparatuses may include a first speaker that receives an input signaland generates sound creating a vibration force, a second speaker or anactuator located near the first speaker for generating a vibration forceto either counteract or reinforce the vibration force of the firstspeaker, a microphone, and an accelerometer for measuring the amount ofvibration.

Generally, functions described herein (for example, the featuresillustrated in FIGS. 1-5) can be implemented using software, firmware,hardware (for example, fixed logic, finite state machines, and/or othercircuits), or a combination of these implementations. In the case of asoftware implementation, program code performs specified tasks whenexecuted on a processor (for example, a CPU or CPUs). The program codecan be stored in one or more machine-readable memory devices. Thefeatures of the techniques described herein are platform-independent,meaning that the techniques may be implemented on a variety of computingplatforms having a variety of processors. For example, implementationsmay include an entity (for example, software) that causes hardware toperform operations, e.g., processors functional blocks, and so on. Forexample, a hardware device may include a machine-readable medium thatmay be configured to maintain instructions that cause the hardwaredevice, including an operating system executed thereon and associatedhardware, to perform operations. Thus, the instructions may function toconfigure an operating system and associated hardware to perform theoperations and thereby configure or otherwise adapt a hardware device toperform functions described above. The instructions may be provided bythe machine-readable medium through a variety of differentconfigurations to hardware elements that execute the instructions.

While the foregoing has described what are considered to be the bestmode and/or other examples, it is understood that various modificationsmay be made therein and that the subject matter disclosed herein may beimplemented in various forms and examples, and that the teachings may beapplied in numerous applications, only some of which have been describedherein. It is intended by the following claims to claim any and allapplications, modifications and variations that fall within the truescope of the present teachings.

Unless otherwise stated, all measurements, values, ratings, positions,magnitudes, sizes, and other specifications that are set forth in thisspecification, including in the claims that follow, are approximate, notexact. They are intended to have a reasonable range that is consistentwith the functions to which they relate and with what is customary inthe art to which they pertain.

The scope of protection is limited solely by the claims that now follow.That scope is intended and should be interpreted to be as broad as isconsistent with the ordinary meaning of the language that is used in theclaims when interpreted in light of this specification and theprosecution history that follows, and to encompass all structural andfunctional equivalents. Notwithstanding, none of the claims are intendedto embrace subject matter that fails to satisfy the requirement ofSections 101, 102, or 103 of the Patent Act, nor should they beinterpreted in such a way. Any unintended embracement of such subjectmatter is hereby disclaimed.

Except as stated immediately above, nothing that has been stated orillustrated is intended or should be interpreted to cause a dedicationof any component, step, feature, object, benefit, advantage, orequivalent to the public, regardless of whether it is or is not recitedin the claims.

It will be understood that the terms and expressions used herein havethe ordinary meaning as is accorded to such terms and expressions withrespect to their corresponding respective areas of inquiry and studyexcept where specific meanings have otherwise been set forth herein.

Relational terms such as first and second and the like may be usedsolely to distinguish one entity or action from another withoutnecessarily requiring or implying any actual such relationship or orderbetween such entities or actions. The terms “comprises,” “comprising,”and any other variation thereof, are intended to cover a non-exclusiveinclusion, such that a process, method, article, or apparatus thatcomprises a list of elements does not include only those elements butmay include other elements not expressly listed or inherent to suchprocess, method, article, or apparatus. An element preceded by “a” or“an” does not, without further constraints, preclude the existence ofadditional identical elements in the process, method, article, orapparatus that comprises the element.

The Abstract of the Disclosure is provided to allow the reader toquickly identify the nature of the technical disclosure. It is submittedwith the understanding that it will not be used to interpret or limitthe scope or meaning of the claims. In addition, in the foregoingDetailed Description, it can be seen that various features are groupedtogether in various examples for the purpose of streamlining thedisclosure. This method of disclosure is not to be interpreted asreflecting an intention that any claim requires more features than theclaim expressly recites. Rather, as the following claims reflect,inventive subject matter lies in less than all features of a singledisclosed example. Thus, the following claims are hereby incorporatedinto the Detailed Description, with each claim standing on its own as aseparately claimed subject matter.

What is claimed is:
 1. A system comprising: a microphone; a firstspeaker having a first mass, the first speaker configured for receivinga first input signal; and a second speaker having a second mass, thesecond speaker configured for receiving a second input signal; and asignal transformation unit for transforming the first input signal intothe second input signal; wherein: the first speaker and the secondspeaker are positioned back to back with the first speaker facing afirst direction and the second speaker facing a second direction that isopposite that of the first direction, and the second speaker isconfigured so that, in response to the second input signal, the secondspeaker generates a second vibration force that is in an oppositedirection to that of a first vibration force generated by the firstspeaker and offsets at least part of the first vibration force generatedby the first speaker.
 2. The system of claim 1, wherein the signaltransformation unit is a transform function.
 3. The system of claim 1,wherein the signal transformation unit is a low-pass filter.
 4. Thesystem of claim 1, further comprising a mechanical coupling measurementunit.
 5. The system of claim 4, wherein the mechanical couplingmeasurement unit measures an amount of vibration caused by the first andthe second speakers.
 6. The system of claim 4, wherein the mechanicalcoupling measurement unit is an accelerometer.
 7. The system of claim 4,wherein the second mass is approximately equal to the first mass.
 8. Asystem comprising: a microphone; a first speaker configured forreceiving a first input signal and generating a first vibration force; asignal transformation unit receiving the first input signal andperforming a signal transformation thereon to produce one or moretransformed input signals for varying an amount of mechanical vibrationat the microphone; and a second speaker configured for receiving one ofthe one or more transformed input signals and generating a secondvibration force; wherein: a combination of the first vibration force andthe second vibration force varies the amount of mechanical vibration atthe microphone.
 9. The system of claim 8, wherein the combination of thefirst vibration force and the second vibration force reduces the amountof mechanical vibration at the microphone.
 10. The system of claim 8,wherein the combination of the first vibration force and the secondvibration force increases the amount of mechanical vibration at themicrophone.
 11. The system of claim 8, wherein the second speaker isconeless.
 12. The system of claim 8, further comprising a mechanicalvibration measurement unit that measures the amount of mechanicalvibration.
 13. The system of claim 8, further comprising a third speakerconfigured for receiving a second one of the one or more transformedsignals and generating a third vibration force, wherein the combinationof the first vibration force, the second vibration force, and the thirdvibration force varies the amount of mechanical vibration at themicrophone.
 14. A method for varying an amount of mechanical couplingbetween at least one microphone and one or more speakers in aspeakerphone comprising: receiving an input signal; sending a copy ofthe input signal to a first speaker; determining if a signaltransformation is needed for the input signal to vary an amount ofmechanical coupling; upon determining that the signal transformation isneeded, performing the signal transformation on the input signal toproduce a transformed input signal; and transmitting the transformedinput signal to a second speaker; wherein the first speaker generates afirst vibration force, the second speaker generates a second vibrationforce, and a combination of the first vibration force and the secondvibration force varies the amount of mechanical coupling between the atleast one microphone and the one or more speakers.
 15. The method ofclaim 14, further comprising measuring an amount of vibration.
 16. Themethod of claim 15, wherein performing the signal transformationcomprises transforming the input signal based at least in part on theamount of measured vibration.
 17. The method of claim 14, whereinvarying the amount of mechanical coupling between the at least onemicrophone and the one or more speakers in the speakerphone includesreducing the amount of mechanical coupling.
 18. The method of claim 14,further comprising determining if the microphone is being used.
 19. Themethod of claim 18, wherein varying the amount of mechanical couplingbetween the at least one microphone and the one or more speakers in thespeakerphone includes increasing the amount of mechanical vibration, ifit is determined that the microphone is not being used.